Research explores mechanics of nanomaterials

When building devices smaller than the thickness of a human hair, it's good to know that the materials chosen for the task will be resistant to cracking. Graduate student Francis Tambwe (right) is conducting research on the mechanics of nanomaterials with his advisor, Associate Professor Donald Stone (left) and Engineering Physics Professor Walter Drugan. The approach combines materials science and theoretical mechanics concepts to explore the fracture properties of nanoscale-multilayered materials. Stone says fracture is the key mechanical behavior issue associated with such materials. The development of novel nanoscale-multilayered materials for use in microelectrical and micromechanical devices that are reliable in practice cannot proceed without a clear understanding of the fracture properties of such materials.

Working in the cleanrooms of the Wisconsin Center for Applied Microelectronics, Tambwe sputters layered metallic composites onto silicon wafers. The silicon is removed, leaving an ultra-thin film composite composed of nickel and copper which is then carefully fractured and analyzed. The goals are to gain an understanding of the key material properties and microscale phenomena that control fracture toughness and an ability to match quantitatively the experimental measurements. The research is funded as a seed project under the National Science Foundation Materials Research Science and Engineering Center (MRSEC) at UW-Madison. The center was established by NSF to carry out research in the formation, characterization and exploration of materials at the nanoscale--the scale of individual atoms. It aims at the fundamental understanding of topics of substantial technological importance and at the communication of this understanding to the public.